This invention relates to in-ear hearing devices, and relates to the fitment, in the ear, of such devices. In this context, the term hearing device includes hearing protection devices, for preventing loud noises from damaging a person""s hearing, particular in the work-place; and includes hearing aids.
Hearing protection devices are often passive (i.e not powered) and some may simply amount to a plug in the ear; while more sophisticated (but still passive) HPDs may include acoustic chambers and filters, for passing or attenuating selected frequencies.
The term hearing device includes active devicesxe2x80x94either of a hearing protection nature, or of a hearing aid naturexe2x80x94in which the some or all of the batteries and other components are mounted behind the ear, or remotely, in a box, which communicates with the in-ear unit by means of a sound-tube, or by wires; and includes active devices in which a microphone, speaker, and all the associated sound-processing circuitry and components, including a battery, are contained within the in-ear unit.
It is recognised that the performance of all in-ear hearing devices, both noise-protectors and hearing-aids, is highly dependent upon the fit of the device in the ear. Conventionally, it has generally been the case that an in-ear hearing-aid is custom-fitted to the individual patient or client. However, custom-fitting is an expensive and time-consuming process. The custom-fitting process is so cumbersome that accepting a poor fit often seems a better alternative than going through the fitting process again.
Using the conventional custom-fitment system, a well-fitting hearing-aid can provide excellent performance; however, the problem is that many hearing-aids do not fit properly. Thus the traditional problem has been in a lack of consistency as to the quality of the physical fit. Recent trends in digital hearing devices seek to overcome the traditional inconsistency-of-fit problem by providing multi-channel sound transmission, one of the channels being used to prevent feed-back. The invention seeks to overcome the traditional inconsistency-of-fit problem by making it possible for the fit to be consistently good.
Conventional custom-fitment, as a process, is somewhat unpleasant, requiring that wet silicone be injected into the ear. The silicone impression of the ear-canal is then sent away to a manufacturing facility, and it can take several weeks, after the fitting appointment, to produce the in-ear device. Also, the custom-fitment aspect of the consultation often takes an inordinate part of the hearing-health-practitioner""s (not to mention the client""s) time, which might perhaps be better spent on evaluation and refinement.
Millions of workers in industry are exposed to noise levels that can damage their hearing. Of course, hearing protection devices are available. However, individual or custom-fitment of conventional HPDs has been problematic and expensive. Conventionally, HPDs have therefore had to be provided on a one-size-fits-all basis, or at least on the basis of a few sizes fit all. If an individual person happened not to fit the range of standard shapes and sizes available, his hearing was not as well protected.
Another problem with conventional HPDs is that it is difficult to tell just what is the performance of the device. The HPD might be very good, theoretically, at preventing sound at one end of the HPD from reaching the other end of the HPD, but if the HPD is a poor fit, sound simply by-passes around the HPD. The tendency therefore is for the HPD to be too tight, which leads to poor wearer-comfort, whereby the wearer tends not to keep the HPD in for long periods.
Whereas a conventional custom-fitted in-the-ear hearing-aid is of hard rigid moulded plastic, conventional HPDs generally have been of flexible construction, being resiliently compressible. The compressible HPD is squeezed into the ear-canal, where it expands, and fills the canal. However, during use, the constant pressure outwards, against the ear-canal, is uncomfortable, and again the wearer tends not to want to keep the HPD in for long periods.
From a factory-safety standpoint, verification of proper initial fitment, and of proper day-to-day wear fitment, is very difficult with the conventional HPDs. Inspections by safety officers are subjective, and are of little use as evidence of proper fitment and use, and still less of effectiveness. An improper fit results in poor protection, as well as discomfort for the user, which in turn encourages non-compliance with hearing protection programs.
From the performance standpoint, HPDs, like hearing-aids, really have to be custom-fitted. This is generally acknowledged as a fact. But, conventionally, custom-fitting of HPDs could hardly be justified on economic grounds.
The invention is aimed at providing a system for fitting devices into the ear, in which the performance of the device is maximised, insofar as the performance is affected by the good fit of the device in the ear-canal, but in which the above mentioned disadvantages as to cost and cumbersomeness of the fitment process are minimised.
As will become clear, the fitment process as described herein is so effective, and yet so inexpensive, and so fast, that the system is economically and practically suitable for the custom-fitment of HPDs having excellent performance to the whole work force personnel of a factory.
When the invention is applied in the field of hearing-aids, because the fitment process is so rapid, and so easy, the practitioner can try the client out with several types and configurations of hearing-aid, each of which can, if so desired, be evaluated by the practitioner, and by the client, there and then, all in a single consultation session. As a result, it can be expected that the percentage of clients who receive close to the maximum possible hearing benefit that can be obtained, given the current state of hearing-aid technology, will be much higher than hitherto.
As mentioned, recent developments in digital hearing aids are aimed at by-passing the need for a good fit, by eliminating feedback. However, the likelihood of consistently good fits, which is an aim of the invention, opens up other avenues of development. In fact, it has been suggested that the audio side of hearing-aid technology, especially for the mass market, has become stalled, in the sense that there is little point in developing components of greater performance, because the devices often fit so poorly in the ear that enhanced performance could hardly be utilised. The expectation that a good fit can be achieved quickly, every time, gives a new incentive to the development of the audio side of hearing-aid (and hearing-protection) technology.